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What happens when during RTH the battery runs out?

Steve M

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Sorry, probably a stupid newby question, covered a thousand times, but if after looking at my M2Z screen and my phone,
after hitting RTH and then I think that it may not make it back , what is the best thing to do?
I'm just trying to plan ahead after reading some horrible stories. I'm not sure what the software is programmed to do.
 
Sorry, probably a stupid newby question, covered a thousand times, but if after looking at my M2Z screen and my phone,
after hitting RTH and then I think that it may not make it back , what is the best thing to do?
I'm just trying to plan ahead after reading some horrible stories. I'm not sure what the software is programmed to do.
It would most likely auto land before the battery runs out completely. It will fly towards home til the critical level triggers the auto land. It could be a rough landing though depending on where it decides to land. You could always emergency land it yourself. Wait til it goes into auto landing then just point the camera down, look around, move the sticks, and try to position it over a flat surface.
 
The drone lands where it is, you can try to steer it to a better landing place by working with the left joystick to keep it in the air and with the right joystic steer it where you want, but when the battery has no more to give, then it settles on the ground.
 
Hopefully on a dry surface, not in water.

In other words, you fly over water, make sure your drone is equipped with pontoons and that you have a boat so you can fish up the drone.
 
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I'm not sure what the software is programmed to do.
If your drone is still flying (RTH or not), when the battery reaches critical low voltage the drone will stop flying forwards and autoland where it is.
So plan to have your drone back before critical low voltage.
 
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In a flyaway situation where the wind would not allow my drone to come back, it eventually landed in the sidewalk about 1500 feet from where I was. I went to get it, and it was waiting for me a few minutes later. It was a lucky episode many mistakes in my part, I setup return home high! Now I don't even use it if I have signal.
 
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In other words, you fly over water, make sure your drone is equipped with pontoons and that you have a boat so you can fish up the drone.

Not a bad idea, but Pontoons can add to a flights difficulty, with greater wind resistance (battery drain) and fighting too much in RTH with wind (again battery drain much faster).

In reality, it is far better when "you fly over water, make sure you plan the flight properly . . . take wind speed and direction into account (fly out against the wind, return with it), and always RTH by flying manually or using the RTH function with plenty of battery safety margin."

If flying over the ocean of other large flat water areas, set RTH to a minimum, this keeps it out of higher winds.
 
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I just want to point out 2 thing's related to low battery ...

1. Be aware that the battery % auto land threshold is determined by height ... the lower you fly the lower your battery % will go until it auto lands.

2. Then it's always better to give up (if over solid ground) & by your self scout out a good landing spot and put it down before any auto land starts. If you take this decision, start with switching the failsafe RTH action to "Land" instead of "RTH" ... then initiate landing. If you don't change the failsafe RTH action the AC will after losing RC connection (which likely will happen when height is low enough to go out of LOS) cancel the manual land command & regain RTH height & start over going home.
 
I was flying my MP2Z Other day when I was quite a ways out it said low battery returning home. So it knows how much battery it’s going to take to come back home. I landed at 25% left. Actually I was kind of surprised Did that.
 
I was flying my MP2Z Other day when I was quite a ways out it said low battery returning home. So it knows how much battery it’s going to take to come back home. I landed at 25% left. Actually I was kind of surprised Did that.
One thing the Mavic is not intelligent enough to know is if your outbound leg was into the wind, or with it. There are many stories in this Forum, of Mavic's not making it home because the outbound leg had the wind behind, but the head-wind coming home was too much. Your situation sounds like you had a headwind on the way out ...
When I trained as a Private Pilot, my Instructors always told me that it was better to do a planned forced-landing than have it thrust upon you due to the tanks going dry and the motor stopping! Same with your Drone - if you know you are not going to make it back, then you need to look for landmarks and open spaces. Remember that if you can keep the Mavic powered 'till it lands, you have a better chance of using the Go4 app's Map & 'Find my Drone' facility. Snap some photo's as you go down too - as those will be accessible through Go4.
 
I'm just trying to plan ahead...
The best planning ahead possible is to know your environment, equipment, and surroundings so that you never get in that situation:
  • Always take off with 100% battery and watch the level carefully. Plan your flight so that you are back to the home point and landing with 30% left.
  • Know the winds at ground level and aloft. If strong winds are present, always try flying upwind first.
  • If/when you don't follow the two recommendations above, always heed the warnings that DJI Go gives you. If it says "High Wind Warning" then get lower and return home. If it says low battery and wants to return home, don't cancel it.
I'm not sure what the software is programmed to do.
Read the manual. The entire RTH process is explained. In this case, Page 15 applies.

after hitting RTH and then I think that it may not make it back ,
In general, I believe in knowing how RTH works and how to activate/deactivate it for a true emergency, but don't rely on it for every return flight. You will become a much better pilot if you learn how to navigate it home manually.
 
Not a bad idea, but Pontoons can add to a flights difficulty, with greater wind resistance (battery drain) and fighting too much in RTH with wind (again battery drain much faster).

In reality, it is far better when "you fly over water, make sure you plan the flight properly . . . take wind speed and direction into account (fly out against the wind, return with it), and always RTH by flying manually or using the RTH function with plenty of battery safety margin."

If flying over the ocean of other large flat water areas, set RTH to a minimum, this keeps it out of higher winds.
Agree... over water the GetterBack is my solution as it is light and doesn’t noticeably change flight characteristics. The pontoons also won’t keep water out of the drone except in near dead calm water conditions.
 
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In general, I believe in knowing how RTH works and how to activate/deactivate it for a true emergency, but don't rely on it for every return flight. You will become a much better pilot if you learn how to navigate it home manually.
This is a very good point. There are many occasions when using RTH can simply make the Mavic rise into a faster headwind and it goes backwards! In some cases, the way to get your Mavic home is to manually fly it down to hedge-top height where the winds are less, and bring it in under full control.
 
Thanks guys, it is all obvious to me now sitting here and reading it all, I just wanted to be sure that there was not something else that I should have been doing in that situation.
During a stress situation I may not think as quickly as I used to.
I liked particularly the advice to point the camera down and take pictures, I may not have thought of that at the time but I will now.
Oh, and to get to a lower altitude if possible.
 
If at all possible, try to fly your outbound leg INTO the wind, so that your DOWNWIND return leg will be helped by the wind.
Also, always adjust your RTH altitude so that you don't waste valuable battery trying to climb to an altitude way higher than you actually need for your particular flying location.
Climbing any higher than what is needed to avoid obstacles is simply a waste of battery power.
 
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In my 1-2 times, it will start landing directly above where it is located at the time of flight back to you and the RTH altitude home you selected. You can then control it back towards you or to a safe spot. To be safe, set your alert at 25% so you have plenty of time to get it home.
 
It would most likely auto land before the battery runs out completely. It will fly towards home til the critical level triggers the auto land. It could be a rough landing though depending on where it decides to land. You could always emergency land it yourself. Wait til it goes into auto landing then just point the camera down, look around, move the sticks, and try to position it over a flat surface.


This is what Ive had to do as well. One thing that MAY help is if you have enough time to tell it wont make it home, is to gain altitude to buy yourself more time to find that emergency landing spot.
 
This is what Ive had to do as well. One thing that MAY help is if you have enough time to tell it wont make it home, is to gain altitude to buy yourself more time to find that emergency landing spot.

How does gaining altitude buy you more time?
 
This is what Ive had to do as well. One thing that MAY help is if you have enough time to tell it wont make it home, is to gain altitude to buy yourself more time to find that emergency landing spot.
Yea I’ve had to do that. During auto land, you won’t be able to gain altitude but pushing up on the stick will maintain the current altitude while you push it home or find a spot to land. In my Mavic Air distance test, I had to land it between a field and a river using only the video feed. Pretty intense feeling lol.
 
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